PLATE XVIII. 
Figs. 1, 1a.—HELASMOSTOMA PALMATUM, Hinde, sp. nov. (Page 243.) 
Fig. 1.—A specimen showing the upper or oscular surface. Natural size. The dermal layer is only 
partly preserved. Several small oysters are attached to it. From the Great Oolite at Hampton Cliffs, 
near Bath. Woodwardian Museum, Cambridge (Walton Collection). 
Fig. la.—A portion of the dermal layer of another specimen, showing three-rayed spicules weathered 
out on the surface. Enlarged 60 diameters. 
Figs. 2—2 c.—LYMNORELLA MAMILLOSA, Lama. (Page 235.) 
Fig. 2.—A large specimen showing the upper surface, with its oseules and ostia. Natural size. From 
the Inferior Oolite, Pea-grit series, at Crickley Hill, near Cheltenham. (Collection Mr. R. F. Tomes.) 
Fig. 2 a.—Portion of a transverse section, showing the tubular excurrent canals or cloace ; the horizontal 
canals and the small incurrent canals connected with the ostia. Enlarged 2 diameters. 
Fig. 2 b.—A vertical section, natural size, showing concentric zones of growth and excurrent canals. 
Fig. 2 c—Portion of a microscopic section, showing the axial spicules and the crystalline condition of 
the fibres. Enlarged 60 diameters. 
Figs. 3—3 d.—LYMNORELLA INCLUSA, Hinde. (Page 236.) 
Fig. 3.—A specimen with a flattened base, showing the upper surface and successive layers of growth. 
Small sunken oscules are shown, and one or two small oysters are attached to the surface. Natural size. 
Inferior Oolite, Pea-grit, Crickley Hill, near Cheltenham. (Collection Mr. R. F. Tomes.) 
Fig. 3a.—The type of the species. Natural size. From the Pea-grit, near Cheltenham. British 
Natural History Museum. 
Fig. 3 b.—Part of a vertical section, showing the disposition of the fibres. Enlarged 10 diameters. 
Fig. 3c.—Part of a thickened fibre, showing the axial three-rayed spicules and the radiately crystalline 
character of the fibre. Enlarged 60 diameters. 
Fig. 3d.—A tuning-fork spicule from the fibre of the same section as 3c. Enlarged 200 diameters. 
Figs. 4—4b.—LyMNORELLA PyemMmA, Sollas. (Page 238.) 
Fig. 4.—A compound specimen, showing the spongites and the dermal layer. Natural size. Inferior 
Oolite, Shipton Gorge. (Collection Mr. E. A. Walford.) 
Fig. 4a.—A specimen showing the conical spongites of the upper surface. Natural size. Inferior 
Oolite, Pea-grit series, near Cheltenham. 
Fig. 4b.—A simple individual. Natural size. Inferior Oolite, at Shipton Gorge. (Collection Mr. E. A. 
Walford.) 
Figs. 5—5d,—LYMNORELLA MICULA, Hinde. (Page 239.) 
Figs. 5, 5a.—Two nodose somewhat lobate specimens, showing traces of zonal layersof growth. Natural 
size. From the Great Oolite at Hampton Cliffs, near Bath. Woodwardian Museum, Cambridge (Walton 
Collection). 
Fig. 5b.—A portion of a vertical section, showing the spicular fibres. Enlarged 60 diameters. 
Fig. 5¢.—A very perfect tuning-fork spicule, from the outer portion of the fibres. Enlarged 200 
diameters. 
Fig. 5 d—Two three-rayed spicules from the surface of the dermal layer. Enlarged 60 diameters. 
Figs. 6—6 b.—_LYMNORELLA RAMOSA, Hinde, sp. nov. (Page 238.) 
Fig. 6.—A specimen seen from the under surface, showing the branches growing from a basal stock. 
Natural size. From the Inferior Oolite at Andoversford, near Cheltenham. Collected by Mr. R. F. Tomes. 
Fig. 6 a.—A portion of the surface, enlarged 10 diameters, showing a group of the larger apertures. 
Fig. 6b.—A portion of a transverse section, showing the spicular fibres. Enlarged 60 diameters. 
